Compartment-specific signaling of striatal opioid peptides in reward-guided behavior

描述（申请人提供）：纹状体整合边缘和感觉运动信息来驱动目标导向的行为。阿片肽及其受体在纹状体中丰富，但内源性阿片信号在行动选择中的明确作用尚未确定。本研究旨在确定小鼠处理边缘信息的纹状体回路的关键组成部分，并了解阿片肽如何在奖励引导行为的背景下改变这些回路。利用基因追踪方法和个体发生工具对大脑切片进行富含阿片类物质纹状体微回路的边缘投影进行系统的解剖和功能分析。新的光化学试剂将与个体发生学结合使用，以识别阿片敏感电路组件，并确定室间体积传递如何塑造阿片信号的时空动态。基因靶向钙成像实验将揭示这些行为如何转化为网络功能的变化。为了为目标导向行为背景下的内源性阿片释放提供证据，在脑切片中观察到在奖励引导任务中观察到的活动模式，同时电生理监测脑切片中的阿片信号。为了确定其功能作用，阿片受体将在奖励引导的行为分析中被阻断，使用一种新的光激活拮抗剂，可以在体内离散纹状体亚区进行短暂抑制。来检测释放和扩散

DESCRIPTION (provided by applicant): The striatum integrates limbic and sensorimotor information to drive goal-directed behaviors. Opioid peptides and their receptors are abundant in the striatum, but a clear role for endogenous opioid signaling in action selection has not been established. This proposal aims to define key components of the striatal circuitry that process limbic information in mice and to understand how opioid peptides alter these circuits in the context of reward-guided behavior. A systematic anatomical and functional analysis of limbic projections to opioid-rich striatal microcircuits will be conducted using genetic tracing methods and ontogenetic tools in brain slices. New photochemical reagents will be employed in combination with ontogenetic to identify opioid-sensitive circuit components and determine how intercompartmental volume transmission shapes the spatiotemporal dynamics of opioid signaling. Genetically-targeted calcium imaging experiments will reveal how these actions translate into changes in network function. To provide evidence for endogenous opioid release in the context of goal-directed behaviors, activity patterns observed during reward-guided tasks will be driven in brain slices ontogenetically while electrophysiological monitoring opioid signaling in brain slices. To identify a functional role, opioid receptors will be blocked during reward-guided behavioral assays using a new photoactivatable antagonist that enables transient inhibition within discrete striatal sub-regions in vivo. To detect the release and spread of endogenous opioids with high sensitivity good spatiotemporal resolution, optical sensors will be developed by chemically modifying receptors so that they report the presence of endogenous agonists. A chemical- genetic strategy for cell-specific pharmacology will be developed to reveal which cellular targets of opioid signaling underlie behavioral responses to opioid peptides and opiate drugs. By targeting native receptors in genetically-identified cells, ths tool provides a powerful means to study opioidergic pathways in the brain. Collectively, these studies will uncover mechanisms by which opioids modulate a neural circuit involved in goal-oriented behavior. By quantifying signaling dynamics in new ways, the role of volume transmission will emerge. Although these novel techniques focus on opioids, the underlying principles are general, and should be applicable to signaling molecules beyond the nervous system. The anticipated findings should facilitate our understanding of disorders in which goal-directed actions are compromised such as Parkinson's and Huntington's diseases as well as attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), and addiction to substances of abuse.